7. 2e AD&D, 1989 (I don't
want to argue as to whether 2e is "really" old school or not. For
purposes of this post, it is).

Let's look at how each
deals with three basic issues:

1. Basic Armor Effectiveness

Each edition assumes that there is a
continuum of armor "classes" and that one may make oneself
harder to kill by wearing armor of a higher (or lower, depending on how
the terminology is used) class. It should be noted, however, that in the
Man to Man Melee Table in Chainmail (p. 41), there are exceptions to this for
certain weapons. For example, while, say, a dagger has a 72% chance of killing
an unarmored opponent vs. only a 3% chance of killing an opponent wearing plate
armor, a two-handed sword has an unchanged 72% chance to kill whether the
opponent is unarmored or wearing plate, and a mace actually has an increased
chance to kill the armored opponent-42% against unarmored and 58% against
plate. On average, however, armor is helpful.

Originally, each class didn't merely represent a place on the continuum but
represented a specific armor type or combination of armor types, or at least it did for armor-wearing men and some armor-wearing humanoids. Thus Armor
Class 7 simply was leather armor, Armor Class 4 was mail (or
"chain mail") with a shield, and so on. AD&D changed this,
adding more armor types and slightly stretching the continuum. The classes now
ranged from 10 to 2 (as opposed to 9 to 2) and, with the exception of a few
classes at each end of the scale, each now represented a selection of armor
combinations. So, Armor Class 7 was now leather or padded armor + Shield or studded
leather or ringmail. Armor Class 4 was chainmail + shield or
splint mail or banded mail. And so on.

2. Variable Damage by Weapon

In Chainmail, the 3LBB's, Holmes and the introductory weapon rules of Moldvay/Cook, all
weapons do the same damage-1-6 points (or for Chainmail, simply, a
"kill"). Though, notoriously for Holmes, if calculating damage per
turn as opposed to per strike, the expected damage per turn of weapons
ranges from 2-12 to half of 1-6. (Small weapons-daggers, etc.-strike twice per
turn and heavy weapons-halberds, etc.-only strike once every other turn. Interestingly, this
yields results for relative weapon effectiveness that are almost the reverse of
the other editions.) Holmes also implicitly states that his combat rules
are somewhat simplified and explicitly directs those desiring more detail
to consult AD&D. Greyhawk and AD&D have variable weapon damages ranging
from 1-2 to 3-18. For the optional or advanced weapon rules in Moldvay/Cook there is a smaller spread-1-4 to 1-10.

3. Variable Weapon Effectiveness vs.
Different Armor Types

The idea here is that while bettering
one's armor class is on average a good thing, it may be relatively more (or
less) helpful depending on precisely which weapon is being used against it. Or
conversely, some weapons will be relatively better than others at attacking
opponents wearing certain specific types of armor. One standard example
would be that low impact slashing weapons are relatively less effective against
plate armor than, say, blunt weapons. So, an AD&D longsword might on average be
better than an AD&D hammer (because it does more damage) but it's not as much better
(and depending on certain assumptions might even be slightly worse) against a
target wearing plate armor.

On the chronologically ordered list
given above, every other edition-Chainmail, Greyhawk, 1e and 2e-has some table
or method of simulating this.

I would argue that while having a rules
mechanic that simulates variable weapon damage versus different armor types is
laudable and, all things being equal, desirable, each attempt in old school
D&D was a failure. This claim is not really controversial (though no doubt
some would take issue with it). But looking at why each attempt was a
failure may give us clues as to whether or not such an effort could
succeed.

2 comments:

I thought that Delta had come up with an interesting and relatively simple system: http://deltasdnd.blogspot.com/2009/02/proposal-weapons-vs-ac.html Personally I don't care enough about this level of "realism" to worry much.

Zenopus discovered, by examining Holmes's manuscript for the "Basic" D&D that is known by his name, that the issue of combat was garbled by bad editing. The main two discussing the dagger/two-handed sword issue are here and here.